The invention relates to a drafting unit of a spinning machine having several top rollers and bottom rollers and having at least one continuous cleaning belt which is placed around two deflecting rollers held at their shafts, which is driven by means of a friction drive, and which rests with one end approximately tangentially on several top rollers or several bottom rollers.
It is known to clean bottom rollers and/or top rollers of drafting units by means of cleaning belts, so-called cleaning rags. In this known construction of German Patent Document DE-A 35 22 504, it is provided that the cleaning belt is placed around two deflecting rollers which are held on the loading arm which carries the top rollers by means of spring elements. The spring elements provide that the cleaning belt is tensioned. The drive of the cleaning belt is derived from a top roller.
It is an object of the invention to develop a drafting unit of the initially mentioned type in such a manner that a simple holding device is provided for the cleaning belt or belts, in which case, however, the cleaning function is not impaired at the same time.
This object is achieved in that at least one of the deflecting rollers is held in the vertical direction by means of the cleaning belt wound around it and, by means of a guide applied to its shaft, is guided such that an end of the cleaning belt rests against the top rollers or the bottom rollers.
By means of this development, it is achieved that, on the one hand, the cleaning belt is tensioned by the inherent weight of one deflecting roller so that, on the one hand, a secure transmission of the driving forces to the cleaning belt is ensured while, on the other hand, this cleaning belt also rests with sufficient force against the surface of the top rollers or bottom rollers to be cleaned. Spring elements or the like for the contact-pressing or tensioning of the cleaning belt are not required.
In a further development of the invention it is provided that one of the deflecting rollers is supported against a drive shaft. The cleaning belt therefore receives its own drive which is independent of the drive of the top rollers or bottom rollers so that speeds and/or moving directions which are suitable for the cleaning function can be selected.
In an expedient development of the invention, it is also provided in this case that the deflecting roller supported against the drive shaft is provided with ring collars moving against the drive shaft. By way of these ring collars, on the one hand, the friction drive takes place from the drive shaft while, on the other hand, the ring collars also have the purpose of causing the cleaning belt to be guided laterally.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.